The present invention relates to a wireless initiation system, a wireless initiation method, and a detonator and an explosive unit used therein for tunneling.
In the related art, there is a blasting method used for drilling a plurality of blast holes with a diameter of approximately several centimeters and a depth of approximately several meters in a blasting face (which is a tunnel working face) in a boring direction, charging explosives into the blast holes, the blasting of the explosives being able to be wirelessly initiated, wirelessly transmitting an initiation signal from a remote position apart from the blasting face, and exploding the blasting face at a tunnel boring site or the like.
For example, in a signal transmission antenna for a remote wireless initiation system disclosed in JP-A-2001-127511 (Patent Literature 1), a loop antenna of an initiation signal transmitter is disposed close to the entire circumference of a tunnel wall face in such a manner that all of wireless initiating detonators charged into blast holes of a blasting face can stably receive energy even if magnetic energy is small.
In a remote wireless initiation apparatus disclosed in JP-A-2001-153598 (Patent Literature 2), a signal transmitter transmits a control signal requesting a reply signal indicative of a state of charge of electric energy of each wireless detonator, a blast preparation instruction signal is transmitted to each wireless detonator after the completion of the charging of all of the wireless detonators is confirmed, and an initiation signal is transmitted to each wireless detonator after a blast preparation completion signal is received from all of the wireless detonators.
JP-A-2001-330400 (Patent Literature 3) discloses a technology in the related art regarding an antenna, fixedly installed on the ground in a tunnel, for a remote wireless initiation system.
In a signal receiving coil of a wireless detonator disclosed in JP-A-8-219700 (Patent Literature 4), the frequency of the coil is less than or equal to 10 kHz, the number of turns of the coil is 100 turns to 100000 turns, the diameter of the coil is φ 35 mm to φ 47 mm, and the length of the coil is 5 mm to 300 mm.